If I read it correctly, then I think that as of last Friday, then no ice houses(including portables) are allowed on the ice after midnight and before an hour before sunrise. So, this means that if you are night fishing in your portable and the clock strikes midnight, you have to pack it up until the morning But...you can sit in a chair or on a bucket next to your 5000lb. vehicle and fish all night Someone please correct me if I am wrong.

Licensed fish houses may be left on lakes unattended until Feb. 29 south of State Highway 200 and until March 15 on lakes north of Highway 200. After the date when ice or fish houses or shelters must be removed, portable shelters may be placed on the ice and used from one hour before sunrise to midnight, but only if there is an open fishing season on the lake.

As for the latest press release from the DNR on ice houses...

Minnesotas ice fishing shelter removal dates are fast approaching. Dark houses, fish houses and shelters must be off the ice of inland waters no later than midnight on Feb. 29 in the southern two-thirds of the state and March 15 in the northern third, according to the Minnesota Department of Natural Resources (DNR).

The DNR also reminds anglers to keep waterways clean by picking up litter around their shelters. Litter on lakes tarnishes natures beauty, destroys wildlife habitats and ruins many opportunities for recreation. Litter is a misdemeanor with a fine of up to $1,000.

The Feb. 29 removal deadline applies to waters south of a line starting at the Minnesota-North Dakota border near Moorhead along U.S. Highway 10, then east along Highway 34 to Minnesota Highway 200, east along Highway 200 to U.S. Highway 2, and east along Highway 2 to the Minnesota-Wisconsin border near Duluth. The March 15 deadline applies to waters north of that line.

If houses or shelters are not removed, owners will be prosecuted and the structure may be confiscated, and removed or destroyed by a conservation officer. Contents of the structure may be seized and held for 60 days; if not claimed by the owner within that time, the items become property of the state of Minnesota.

After the date when ice or fish houses or shelters must be removed, portable shelters may be placed on the ice and used from one hour before sunrise to midnight, but only if there is an open fishing season on the lake. Storing or leaving fish houses or dark houses on a public access is prohibited.

Anglers are encouraged to monitor ice conditions on lakes and make arrangements to remove their houses before travel on the ice is dangerous. The DNR recommends a minimum of 4 inches of good solid ice for ice fishing; at least 5 inches for snowmobiles or ATVs; 8 to 12 inches for a car or small pickup; and 12-15 inches for a medium truck.